Removable computer display interface

ABSTRACT

A portable computer is configured to accept removable modular display panels of different types that plug into a structure hinged to the body of the computer. Each display panel has a sliding engagement means fixed along a lower edge, and the hinged structure has a mating sliding engagement means along an upper edge and parallel to the axis of the hinge, allowing a display panel to engage and disengage in the direction of the axis of the hinge. In an embodiment of the invention, display modules adaptable to the computer have a code stored in a memory device that is accessible on start-up by the computer, to identify and load a display driver routine capable of driving the display module assembled to the computer.

CROSS REFERENCE TO RELATED DOCUMENTS

[0001] This application is a Divisional Application of copendingapplication Ser. No. 08/097,768 filed Jul. 26, 1993, which is adivisional application of Ser. No. 07/918,966, which is now issued asU.S. Pat. No. 5,262,759.

FIELD OF THE INVENTION

[0002] This invention is in the field of architecture of portablecomputers, and pertains in particular to apparatus and methods ofinterfacing removable physical displays to portable computers.

BACKGROUND OF THE INVENTION

[0003] The marketplace for portable computers, such as notebook andlaptop computers, is one of the faster growing sectors of the computerindustry. There are many challenges in developing and designingcomputers of this sort, many of which are a result of need for lightweight, strength, and longevity of portable power sources.

[0004] Another area of innovation in the development of portablecomputers is driven by the facts of use of portable computers ascompared to stationary models. Portable computers have to operate undera variety of conditions. For example, while a stationary model, such asa desktop computer, is typically used at a single location underrelatively constant lighting conditions, a portable computer must beusable under a variety of lighting conditions in both indoor and outdoorsituations. In some situations it is even preferable to have a displaythat is usable in bright sunlight.

[0005] There are several different types of computer displays, and manynew types being developed, all of which are what are called in the art“flat panel” displays. Flat panel displays are necessary, because thewell-known CRT displays are much too bulky and vulnerable to be usedextensively for portable applications.

[0006] Among the many different types are Transflective displays, whichhave low back light and low power consumption; standard monochromepaper-white displays, which are back-lit and exhibit moderate powerconsumption; and passive color displays, also known as super-twistnematic (STN), which have very good visibility and color, but exhibithigher power consumption.

[0007] There are seen to be, then, many issues one must consider whenchoosing a display, such as visibility under different ambientconditions, color availability and range, power consumption, and more.And in the current state-of-the-art, choosing the display is akin tochoosing the computer, because most computers are not provided with arange of choices in display.

[0008] What is clearly needed is a portable computer with a physicalinterface for attaching and detaching a display panel, and a means ofrecognizing on power-up the specific display attached.

SUMMARY OF THE INVENTION

[0009] In a preferred embodiment of the invention a computer system isprovided having a body structure that houses and supports computingelements, memory elements and input elements. The display for the systemis provided as a removable flat panel display module which has physicaland electrical joining elements for attaching to the body structure ofthe computer. The attachment is made to a mounting structure that ishinged to the body structure along a pivot axis, and the mountingstructure has corresponding physical and electrical joining elements toengage those provided on the display module. The physical and electricaljoining elements are aligned to join and disjoin by motion in thedirection of the pivot axis, which provides for secure attachment in theevent a user lifts the computer by the display module.

[0010] In a preferred embodiment the physical mating elements compriseengaging rails with an engaging direction parallel to the pivot axis ofthe mounting structure, and a snap-in structure having a matching slotand a disengagement pushbutton comprising a releasable detent mechanism.The electrical connection is made in this preferred embodiment by amulti-pin connector engaging and disengaging in the same direction asthe engagement rails.

[0011] Also in a preferred embodiment, modular displays for use with acomputer configured to accept them have a code stored in a memorydevice, such as an EEPROM, for identifying the type of display, which isaccessed by the computer memory and matched with a compatible displaydriver routine for operating the display, which the computer then uses.Newly developed displays may then be used with computers previouslymanufactured and sold, by updating the computer BIOS and providingsuitable drive routines for such newly developed displays.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is an isometric view of a portable computer according tothe invention with a removable modular display.

[0013]FIG. 2 is an elevation view of a modular display according to anembodiment of the invention, assembled to a mounting structure.

[0014]FIG. 3A is a view of the same components as shown in FIG. 2, butwith the modular display disjoined from the mounting structure.

[0015]FIG. 3B is a cross-section view through guide and engaging takenalong section line 3B-3B of FIG. 2.

[0016]FIG. 3C is an elevation view of a latching mechanism employed inan embodiment of the invention.

[0017]FIG. 4 is a block diagram depicting an arrangement of elements ofa computer according to an embodiment of the invention, used forinitializing the computer to operate the modular display.

[0018]FIG. 5 is a block diagram of elements of a portable computerconnected to the elements of FIG. 4.

[0019]FIG. 6 is a logic flow diagram depicting steps of a methodaccording to an embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020]FIG. 1 is an isometric view of a notebook computer 11 with aremovable, interchangeable display module 13 according to an embodimentof the present invention, allowing a variety of different types ofdisplay modules to be used with the same computer apparatus simply byremoving one display module and substituting another. Notebook 11 alsocomprises a keyboard 15 and a body portion 19. Display module 13 isshown in the “open” position, but may be rotated “closed” over thekeyboard, where it may be secured by conventional latching mechanisms.

[0021] In the embodiment shown in FIG. 1, display module 13 isconfigured to attach to a hinged mounting structure 17, having an “L”shape, which remains with the computer when display module 13 isremoved. The hinges between body portion 19 and mounting structure 17are not seen in FIG. 1, and may be accomplished in a number ofconventional ways. In a preferred embodiment, the hinge mechanisms arepre-loaded to provide sufficient friction to allow the display, ifreleased at any partially open position, to remain in that position.

[0022]FIG. 2 is a face-on view of the notebook computer in the directionof arrow 21 of FIG. 1, showing more detail of the unique mounting ofdisplay module 13 to mounting structure 17 according to the presentembodiment of the invention. The unique mounting configuration providesfor display module 13 to approach and engage mounting structure 17 fromone side, in this case from the left, and to be removed also from theside, in the direction of arrow 23. FIG. 2A shows the display modulefully engaged.

[0023]FIG. 3A is a view of the notebook computer from the same vantageas in FIG. 2, but showing the display module fully disengaged frommounting structure 17. In this embodiment there are three sets oflinearly engaging guides for guiding the display module into engagement,and for providing structural rigidity when engaged. Guides 25 and 26 areone set, guides 27 and 28 another set, and guides 29 and 30 a third set.Three sets have been found to be convenient. There could be one, two, ormore than three sets of guides in other embodiments.

[0024]FIG. 3B is a section taken through the engaging guide setcomprising guides 25 and 26 to better illustrate the details ofengagement. In this embodiment guide 25 has a T-shape, and guide 26 hasa C-shape, such that the T-shape of guide 25 fits snugly within theC-shape of guide 26. The engaging shapes of the other guide sets followthe same detail as the set shown.

[0025] Although not shown in the Figs. provided, the leading end ofT-shaped guides are tapered for easy entry into the C-shaped guides.Also, there is no necessity for one sort to be attached to the displaymodule and the other to the mounting structure.

[0026] Mounting structure 17 has a vertical portion 18 at one end, anddisplay module 13 has a cut-out area 31 of the same shape and size asvertical portion 18, so when the display module is fully engaged withmounting structure 17 the two form a rectangular assembly. A snap-instructure 32 fixedly attached to display module 13 extends into cut-outarea 31, and aligns with and engages an engagement slot 33 in verticalportion 18 of mounting structure 17 when the display module is fullyengaged.

[0027]FIG. 3C shows additional detail of snap-in structure 32 andengagement slot 33. Structure 32 is injection molded plastic in theembodiment shown, and includes a cantilevered spring-lever 34 with asnap-in shoulder 35. Slot 33 has a shoulder 36 which engages shoulder 35on structure 32 when fully assembled, firmly locking display module 13into structure 17. A spring-loaded button 37 is configured to deflectcantilever spring 34 when the button is depressed, allowing disjoiningof the display module and the mounting structure.

[0028] There is additionally a connector 39 (FIG. 2) with a male (39′)and a female (39″) part (FIG. 3A), for communication, power, and controlsignals between the computer and display module 13.

[0029] To remove a display from the computer, one depresses button 37and slides the display to the side (direction of arrow 23), disengagingsnap-in structure 32 and connector 39, while at the same timedisengaging the three sets of linearly operating guides mounted acrossthe length of structure 17 and the display module When the linearlyoperating guides are disengaged, one may lift the display module awayfrom the computer. To engage the same or another display module, onesets the module in alignment on structure 17 with the matched linearguides adjacent, then slides the module in the direction of arrow 23 toaccomplish engagement. The purpose of having plural sets of engagingguides is to minimize the distance one must move the display module toone side when engaging ad disengaging.

[0030] The particular arrangement shown in FIGS. 2, 3A, 3B, and 3C hasproven to be advantageous, although there are other arrangements alsouseful. One could, for example, use round pins aligned with bores toaccomplish guiding and engaging. In the embodiment shown the height ofportion 18 of structure 17 is about 6 cm., but could extend for the fullheight of module 13.

[0031] A distinct advantage of the sideways engagement and disengagementfor the display module lies in the fact that the engaging guides, suchas guides 25 and 26, may be easily moved in the engagement direction,but are extremely difficult to separate at a right angle to the engagingdirection. The same is true for other engaging devices that might beused, such as pins as mentioned above. One may pick the assembly up bythe display module and carry it that way, because the forces from doingso will be at a right angle to the length of the engagement elements,instead of in line with the direction of disengagement. This is aparticular advantage for the notebook computer.

[0032] In the embodiment shown power and control connection is made fromthe computer to display module 13 through the multi-pin electricalconnector 39 (FIG. 2), shown as male part 39′ and female part 39″ inFIG. 3. In the present embodiment there are 40 pins in the connector,although in some other embodiments there might be more or fewer.

[0033] As described above, the removable nature of the display modulemakes it possible to provide a variety of display modules to be usedwith a single notebook computer. A user may then be offered a number ofpurchase options. One might desire, for example, to have two displaymodules, one capable of providing optimum performance under officeconditions, and another for outdoor use. The replaceable nature of thedisplay module also allows a user to update to higher performance (andperhaps more expensive) displays at a time after purchase. One also hasthe option of interfacing displays to the computer that may be developedat a later time.

[0034] An additional feature of the invention is an ability on power-upto ascertain the nature of the display module and to provide the correctpower and control signals for the assembled module.

[0035]FIG. 4 is a block diagram showing the connection of power andcontrol elements in an embodiment of the invention. In this embodiment adisplay board 41 is incorporated into the computer with connection tothe system parallel bus 52, and having output to 40-pin connector 39along path 40. Display module 13 comprises a flat panel display 43,which, in this embodiment is a component obtained from one of severalsuppliers of flat panel displays. As is typical in the industry, display43 comprises “tabs” such as tab 45, which incorporate logic forconverting data communication to on-off status for crossed traces thatactivate bits in the bit-array of the display. In this embodiment thedisplay emulates to 640 column by 480 line standard of VGA displays.Displays in the art come complete with wiring connections and signalrequirements, including data format and so forth, so the computermanufacturer using the display may provide the correct operatingsignals.

[0036] The display module also comprises circuitry 47, including anadjustable DC/DC converter 49 and a EEPROM memory device 51 for storinga code associated with the type display with which the EEPROM isassociated. Circuitry 47 is connected to connector 39 by path 42, andprovides output to display 43 via path 44. The DC/DC converter receivesa power trace through the connector, and provides output for contrastvoltage and backlighting, which may be adjusted via user signals. Thisoutput is part of the signals on path 44 to display 43. In onevariation, the contrast and brightness are adjustable by keystrokecombinations, and in a more preferred mode, when a pointing device (suchas a mouse) is used, the contrast and brightness may be adjusted bymovement of the pointing device. In both variations, the adjustments aresoftware controlled. There may also be input devices, such as familiarslide switches, on the display module to make such adjustments.

[0037] In the present embodiment EEPROM 51 is programmed with a uniqueidentity code for the specific type of module. Each type of moduleoffered for the computer has a specific identity code. On initializing,the system BIOS queries the display to ascertain the module type, andloads the correct routines to operate that module. For the situationwhere a new type or improved display module is introduced, a simple BIOSupgrade allows previously manufactured computers to use the new displaymodule.

[0038] Typically communication to the display module to control thebit-map of the display is by 8-bit serial data flow. The protocol forthe serial communication, however, is not always the same frommanufacturer to manufacturer and for different display types. Hence theEEPROM code for identity, which the computer system uses as a pointer todriver routines to match the particular requirement of the displaymodule. On power-up, as indicated above, the BIOS queries the displaymodule and loads the correct display driver routines.

[0039] As a further aid in understanding the circuitry for the presentembodiment of the invention, Table I is provided with the present pinnumber assignments related to signal identification. TABLE I PinAssignments No. Pin Description 1 VCC Power to display logic 2 VSSGround to display logic 3 VEN Unused 4 VEP Unused 5 SDE Serial I/O toEEPROM 6 SD1 Serial I/O to EEPROM 7 SD2 Serial I/O to EEPROM 8 CF1Contrast control (analog) 9 CF2 Brightness control (analog) 10 CF3Unused 11 CF4 Unused 12 DEN Display enable 13 FCL Frame clock 14 PCLPixel clock 15 RCL Row clock 16 ACL Modulation 17 UD0 Upper display data0 18 UD1 Upper display data 1 19 UD2 Upper display data 2 20 UD3 Upperdisplay data 3 21 UD4 Upper display data 4 22 UD5 Upper display data 523 UD6 Upper display data 6 24 UD7 Upper display data 7 25 LD0 Lowerdisplay data 0 26 LD1 Lower display data 1 27 LD2 Lower display data 228 LD3 Lower display data 3 29 LD4 Lower display data 4 30 LD5 Lowerdisplay data 5 31 LD6 Lower display data 6 32 LD7 Lower display data 733 RB Raw battery plus 34 RB Raw battery plus 35 RB Raw battery plus 36RB Raw battery plus 37 RBGND Raw battery ground 38 RBGND Raw batteryground 39 RBGND Raw battery ground 40 RBGND Raw battery ground

[0040] In this particular instance, there are two bit streams, one foran upper display, and the other for a lower display, which are notseparate displays at all, but upper and lower segments of the onedisplay, driven in parallel to avoid flicker. The 40-pin arrangement hasproven to also be sufficient to drive color displays, which have,generally speaking, three times the dots in the display map as domonochrome displays.

[0041] There are many changes that may be made in the embodiments of theinvention described above without departing from the spirit and scope ofthe invention. For example, there are several ways the circuitry mightbe arranged to accomplish the task of querying the EEPROM in the displaymodule to determine the display type and drive requirements. Likewise, aEEPROM is convenient for storing the identity code at the displaymodule, but is not the only memory device that might be used. There arealso a number of alternative arrangements of elements to allow displaymodules to engage from one side, as described above. There are similarlymany other alterations that may be made without departing from thespirit and scope of the invention.

What is claimed is:
 1. A portable computer having a computer module anda detachable flat panel display comprising: engagement apparatusincluding mechanical apparatus for attaching said detachable flat paneldisplay to said computer module and a first multi-pin electricalconnector for providing electrical data and command signals between thedetachable flat panel display and the computer module; and controlcircuitry including a memory device in the portable computer; whereinthe control circuitry signals the detachable flat panel display throughone or more pins of the first multi-pin electrical connector to return acode through one or more pins of the multi-pin electrical connector, thecode being stored in a memory in the flat panel display, and wherein thecontrol circuitry selects a driver routine associated with the code andstored in said memory device, and utilizes the driver routine to operatesaid detachable flat panel display.
 2. A portable computer as in claim 1further comprising a detachable flat panel display physically attachedto the portable computer by the engagement apparatus and electricallyconnected to the control circuitry through a second multi-pin electricalconnector mating the first multi-pin electrical connector, thedetachable flat panel display having therein a non-volatile memorydevice containing a code unique to the type of the flat panel display.3. A flat panel display module comprising: physical engagement apparatusfor attaching the display module to a portable computer; a multi-pinelectrical connector for receiving commands and data from the portablecomputer to drive the display; a non-volatile memory device connected toat least one pin of the multi-pin electrical connector and containing acode unique to the type of the display module.
 4. A flat panel displayas in claim 3 wherein the non-volatile memory device is anelectrically-erasable programmable read-only memory (EEPROM).
 5. Amethod for replacing a first modular flat panel display attached to aportable computer with a second modular flat panel display of adifferent type, and of identifying and driving the second modular flatpanel display, comprising steps of: (a) disengaging the first modularflat panel display physically at a mechanical attachment apparatus andelectrically at a multi-pin electrical connector; (b) engaging thesecond modular flat panel display physically at the mechanicalattachment apparatus and electrically at the multi-pin electricalconnector; (c) accessing a code stored in a first memory device in thesecond modular flat panel display from operating circuitry in theportable computer, the code unique to the type of the second modularflat panel display; (d) matching the code with a driver code routineassociated with the code and stored in a second memory device in theportable computer; and (e) executing the driver code routine in theportable computer to operate the second modular flat panel display fromthe operating circuitry in the portable computer.
 6. A portable computeras in claim 2 having an outer case and comprising a hinged mountingstructure pivotally attached to the case, wherein the hinged mountingstructure and the flat panel display module each have mating slide railsarranged for engaging and disengaging by moving the flat-panel displaymodule in the direction of the hinge axis.
 7. A portable computer as inclaim 6 wherein the engagement direction for the first and secondmulti-pin electrical connectors is the same direction as for the sliderails.
 8. In a computer having a flat panel display module hinged toclose over the computer case to provide a compact package for transportand storage, wherein the display module and the computer allow forinterchanging different types of displays, a system for recognizing thedisplay type attached and selecting an appropriate driver protocol, thesystem comprising: a non-volatile memory device in the flat paneldisplay module, the non-volatile memory device containing a code uniqueto the type of the flat panel display module; a plurality of driveroutines stored in a memory of the computer, each drive routineassociated with a unique code; and control circuitry in the computer;wherein the control circuitry in the computer retrieves the code in theflat panel display module, matches the code from the display module withone of the unique codes associated with a drive routine stored in thememory of the computer, and loads and executes the associated driveroutine to drive the attached display module.